MAT 540 MAT540 Week 4 Quiz

MAT 540 Week 4 Quiz

1. Find the standardized variable z if x has Mean 12 and standard deviation 4.
2. Find the area under the standard normal curve to the right of z = 1.55. Round to four decimal places.
3. Find the area under the standard normal curve to the left of z = 2.63
4. Find the area under the standard normal curve over the interval z = −0.53 to z = 0.53. Compute probabilities using the standard normal table in Appendix B (Table 3). Round the answer to four decimal places.
5. Scores on a certain nationwide college entrance examination follow a normal distribution with a mean of 550 and a standard deviation of 100. Find the probability that a student will score over 690.  Round your answer to four decimal places.
6. Scores on a certain nationwide college entrance examination follow a normal distribution with a mean of 500 and a standard deviation of 100. Find the probability that a student will score between 350 and 620.  Round your answer to four decimal places.
7. A population has mean 53 and standard deviation 12.  Calculate the mean of x bar for a random sample of size 10.
8. A population has mean 53 and standard deviation 12.  Calculate the standard deviation of x bar for a random sample of size 12.
9. Suppose the weights of packages of lettuce coming off a packaging line have a normal distribution with mean 8.4 ounces and standard deviation 0.4 ounce. If every package is labeled 9.2 ounces, what proportion of the packages weigh less than the labeled amount?
10. Suppose the weights of the contents of cans of mixed nuts have a normal distribution with mean 32.8 ounces and standard deviation 0.4 ounce.
     
    If two packages are randomly selected, what is the probability that the average weight is less than 32 ounces?
     
    Round to one decimal place.